National Qualifications Computing Science - Glow Blogs · 2019-12-20 · National 5 Computing...

National Qualifications

CS(N5)14BMS Computing Science

Marking Instructions

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Number Question Instructions Marks

1 Convert the value 42 into an 8-bit binary number. Show your working.

00101010 (1 mark) 1

2 Name the part of the processor that deals with comparisons.

ALU (1 mark) 1

3 State one problem associated with storing data in a flat file database.

• Data duplication – storing same data multiple times.

• Deletion anomalies (deleting last record of a required item of data)

• Modification anomalies (amending only one occurrence of an item of data that appears multiple times).

• Insertion anomalies (unable to insert data because other attributes are not available).

Any one bullet for 1 mark 1

4 When ordering cloths online, users select their choice the following drop down menu:

State one advantage of this type of user interface.

Unable to select an invalid value. Only valid choices are available. (1 mark)

1

5 Paul is developing a new website. Before deploying the new website he ensures that the site matches the original design. Describe one other type of test that Paul should ensure is carried out.

Test links to ensure go to the correct locations / testing the navigation (1 mark)

1

National 5 Computing Science CS(N5)13AMS

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6 State the purpose of the mod operator shown in this section of code.

spare = number_seats MOD number_of_plates

Mod shows the remainder part when number_seats / number_of_plates is an integer value.

Accept an example: 5 mod 2 would be 1 as integer part is 2 and remainder is 1.

Candidate must include reference to the precedence of the variables

1 mark 1

7 Calculate the backing storage required for a 16-bit colour image 800 pixels by 200 pixels.

Express your answer in Kilobytes.

800 x 200 = 160000 pixels (1 mark)

16 x 160000 = 2560000 bits (1 mark)

2560000 / 8 = 320000 bytes

320000 / 1024 = 312.5 Kb (1 mark)

Max 3 marks 3

8 Pseudocode is often used when creating the design of a program.

a State another design notation that could be used when designing a program.

• Structure diagram • Other valid


b Describe one advantage of using this design notation instead of pseudocode.

• Structure diagram: Able to see modular elements of program at high level. Visual presentation of links between code sections.

• Other valid.


9 A web page can use relative and absolute addressing. Explain each of these terms.

A relative address is given in relation to the current page. (The domain would not be included a relative address). (1 mark)

An absolute address is the complete Internet address of a resource including protocol, domain, path and document (1 mark). 2

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10 Harry computer technician for a large company and is concerned about the energy usage of the computers he is responsible for.

Describe two methods Harry could use to reduce the energy use of the computers.

• Reduce time until device does on standby/screen switches off or goes to standby/drives go to standby mode.

• Use of power efficient/low energy components in devices.

• Change power usage profile of devices • Other valid

1 mark each bullet, max 2 marks 2

11 Here is part of a database used to manage the world verses world matches in an online role playing game. (see paper)

Describe how the data has been sorted.

Data has been sorted on:

Rating descending (1 mark) AND

Rank Points descending (1 mark)

Max 2 marks 2

12 State one method of representing characters in a computer system.

• Unicode • ASCII • Other valid


13 Claire has a large audio file and she needs to reduce the size of the file so that she can store it on a USB stick.

State two properties of the audio file she can change to reduce its size.

• Reduce sampling rate • Reduce sampling resolution • Change level of compression (assuming

file is already compressed) • Make file mono rather than stereo.

1 mark for each bullet, max 2 marks 2

14 CitySpoon is an app for eating out in cities around the world. It provides information about local places to eat from street food to à la carte.

When using the app a number of options are displayed based on the users current location. (see paper)


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a Describe two advantages of running this app on a mobile device rather than a desktop PC.

• Easy use for target audience. • Able to use GPS/Location System of

mobile device. • Size/weight—smartphone fits into

pocket and is easily carried on holiday • Internet connection using 3G—access

almost anywhere—desktop PC might only connect using standard network

• Ability to make calls—can contact restuarants referred to in app using same device

• Messaging—can book make resevations and get confirmation message sent directly to phone

• Other valid 1 mark each bullet, max 2 marks

2

b Comment on the suitability of the user interface design shown above for use on a smartphone.

A description of interface feature supported by a judgement of its suitability for smart phone. Evaluations could indicate reasons why interface is suitable for smart phone. • user friendliness • straightforward navigation • consistent design of elements and text • good visual layout Comments could indicate reasons why interface is suitable for smart phone. Size of smartphone screen good for thumbnail images of output, especially Photos. One mark for each valid point up to a maximum of two.

2

c The images the app displays are uploaded to a server the app connects to.

i State a standard file format suitable for storing the photographs.

JPG/PNG/BMP (do not accept GIF)

1 mark 1

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ii Explain why reducing the resolution decreases the time to download the images to the app.

Reducing the resolution reduces the size of the file (1 mark).

If the file is smaller then it takes less time to transmit (because there is less data to transmit) (1 mark) 2

d Explain why the app and the server is an example of a client/server network rather then a peer-to-peer network.

The app is the client and connects to the central server to gather data (1 mark)

In a peer-to-peer network all the nodes are equal so resources can be found any where on the network (1 mark) 2

e Describe one element of good design that could be used to improve the accessibility of the app.

A description of web page feature that helps user access information such as: • Screen magnification/zoom feature to

enlarge what is displayed on the computer monitor, making it easier to read for vision impaired users.

• Voice output option to read text on page making it easier for users with reading or learning difficulties.

• Voice output option to read out text and commands available so site can be use

• Careful choice of colour scheme helps avoid problems with colour blindness and some low vision eyesight issues.

• Careful choice of font helps readability.

One mark for any appropriate feature. 1

15 BattleWars is a role playing game where players engage in combat against each other. The damage received by a player is calculated using the following function. (see paper)

a i Identify the line that stores a value in an array.

Line 260 (1 mark) 1

ii Identify the line that includes a condition.

Line 256 (1 mark) 1

iii Identify which line shows output from the program.

Line 261 (1 mark) 1


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iv Identify which line contains parameters.

Line 254 (1 mark) 1

b When the program was written the programmer mis-typed the > (greater than) symbol on line 256 as < (less than).

State which type of error will have been created by this mistake.

Logic error (as the syntax is correct but the logic of the condition is now not what was intended). (1 mark)

1

c BattleWars players can craft items. The pseudocode below is used to add ‘vitality’ to a crafted item.

(see paper)

i State the type of loop shown above. Conditional loop (1 mark) 1

ii State an input a player could enter to enable the program to continue from line 2013.

Any value >=30 and <=100 i.e. 56 (1 mark)

1

iii State the name of the standard algorithm that this code represents.

Input validation (1 mark) 1

d Another section of code from the BattleWars program is shown below. (see paper).

Describe the operation of the & operator in this code.

& operation concatenates/joins to strings together. (In this case the resulting text will be “Warrior Elf”.

1 mark (accept example). 1

e BattleWars makes use of cloud services instead of local storage for storing game data.

State one benefit of using cloud based storage instead of local storage.

• Can access data from any computer device remotely

• No requirement for own servers • Less need for own technical support on

site • Automatic backup/recovery of data Any bullet for 1 mark 1

16 SnowCo specialise in snow sports holidays sold directly to customers online. A page from the SnowCo website is shown below. (see paper)

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a State the URL of this web page. http://snowco.scot/property/finder.html

(1 mark) 1

b This web page makes use of internal and external hyperlinks.

Explain the difference between an internal hyperlink and external hyperlink.

An internal hyperlink points to a file/another page within a website (1 mark) An external hyperlink points to another website (1 mark)

2

c The site makes use of a number of videos in mp4 format. Describe two advantages of mp4 over avi.

• MP4 generally better support across a number of platforms.

• MP4 is an open standard where AVI is a proprietary standard.

• MP4 has better compression resulting in smaller file sizes than AVI

• Other valid


d The “search” tool on the web page makes use of JavaScript.

Suggest one other place where JavaScript may be used on this page.

• Weather Widget • DropDown Menus • Twitter/Facebook/Email buttons • Other valid

Any bullet for 1 mark 1

e SnowCo stores details of its customers on a database.


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i State one principal of the Data Protection Act with which SnowCo must comply.

• Data must be fairly and lawfully processed.

• Data must only be obtained for one or more lawful and specified purposes.

• Data collected and processed by not be excessive in relation to the purpose of using it.

• Personal data must be accurate and up-to-date.

• Personal data must be processed according the rights of the data subjects.

• Data must be held securely (and with protections in place to ensure against accidental damage).

• Data must not be transferred outside the EEA unless covered by data laws in that country.

Any 1 bullet for 1 mark 1

ii Explain why compliance with this principal is important to customers.

Answer should be appropriate to response given in (i) above.

1 mark 1

f A search is carried out for the details of ski resorts in France and Italy. Here are some of the matching resort details. (see paper)

Describe how the list above is sorted.

Ascending Snowfall (1 mark) Then on Elevation Descending (1 mark)

2

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17 Harry has been asked to write a program to calculate the costs for a wood carving business. The program will store the costs involved in producing wooden ornaments for gardens.

The following calculations will be used to output the costs involved for each ornament.

Material Cost = (Wood Cost + Varnish Cost + Tools Cost) / Number Made

Total Cost = Labour Cost + Material Cost

a State the number of variables Harry would require for this program.

7 variables (1 mark) 1


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b Using pseudocode or a programming language of your choice, write a program to enter the required data, then calculate and display the total cost.

RECEIVE wood_cost FROM (REAL)KEYBOARD

RECEIVE varnish_cost FROM (REAL)KEYBOARD

RECEIVE tools_cost FROM (REAL)KEYBOARD

RECEIVE number_made FROM (INTEGER)KEYBOARD

RECEIVE labour_cost FROM (REAL)KEYBOARD

5 values as input (2 marks)

SET material_cost = (wood_cost + varnish_cost + tools_cost) / number_made

1 mark

SET total_cost TO labour_cost + material_cost

1 mark

SEND total_cost TO DISPLAY

1 mark

Maximum 5 marks

5

c While the program is being developed, Harry carries out occasional test runs.

State the type of translator you would recommend Harry uses in this situation.

Explain your answer.

Interpreter (1 mark)

Explanation:

• An interpreter reads and executes source code without the need to translate the entire program first.

• When errors are encountered the interpreter stops, providing feedback on the error, which helps with debugging.


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d One of Harry’s colleagues suggests that his code is not readable. Name and describe two methods of improving the readability of code.

• Indentation / White space • Meaningful variable names • Internal commentary


18 Drones are small radio controlled and programmable flying robots that can be fitted with a number of devices.

a The drone is fitted with a camera, altitude sensor and a global positioning system.

State the hardware that allows these external devices to be connected to the drone’s computer system.

Interface (1 mark)

1

b The drone can be programmed to carry out security patrols over buildings and transmit video from its camera back to a security office for monitoring.

Highlight one technical issue of using wireless technology to transmit the video from the camera.

• Maximum distance for WIFI connection • Best in “line of sight”. Obstacles

between drone and wireless receiver may lead to reception issues.

• Requirement for a wireless receiver to communicate with drone.

• Bandwidth of Wireless connection (will need to be relatively high to support video).

• Other valid.



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c This program is created for the drone to complete a security patrol. The programming language used with the drone has the following pre-defined functions.

advance(n) n = distance in meters to move in current direction

rotate(d) d = degrees to turn (positive means clockwise)

ascend(m) m = distance in meters to move (positive means up)

The path the drone takes is shown on this map. (see paper)

i Write the code for the drone to follow an octagon patrol path.

Octpatrol(n)

FOR side FROM 1 TO 8 DO

move(n)

rotate(45)

END FOR

1 mark for FOR/END FOR 1 mark for move(n) 1 mark for rotate(45)

3

ii The following program uses the Hexpath(n) function to create a new patrol path.

Two values have been missed out from the code.

Complete the code by filling in the values in the two boxes.

Box 1: REPEAT 3 Times

Box 2: rotate 120

1 mark each box, max 2 marks

2

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d The drone software includes a firewall. Describe two ways that a firewall will prevent unauthorised access to the drone.

• Block specific IPs from accessing • Block access to specific ports available

on the drone • Block specific protocols from access

drone • Other valid


e A security protocol is used when communicating with the drone. Explain the purpose of a security protocol.

A security protocol ensures that exchanges between the drone and others are encrypted (and cannot be understood if intercepted by a third party) (1 mark) 1

19 The Game Mag are a computer games magazine who publish reviews and articles about computer games. Game Mag want to store the details of computer game publishers and computer games which they review.

Some sample data is shown in the table below. (see paper)

a To avoid data duplication, a database with two linked tables is proposed – PUBLISHER table and GAME table

i List the fields/attributes that should be included in each table.

PUBLISHER ( Publisher Code Publisher Logo )

GAME ( Game Number Title Studio Metascore )

1 mark for each correct table, max 2 marks 2

ii Identify the foreign key used to link the two tables.

Publisher Code (1 mark) 1

b Name the field type required to store the Logo image.

Object (1 mark) 1


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c The Metascore field must be an integer from 0 to 100.

Name the type of validation that should be implemented on this field.

Range check (1 mark)

1

d Game Mag is running an article about security risks and the computer games industry.

i The article mentions DOS (Denial of Service) attacks on game servers.

Explain what is meant by a DOS (Denial of Service) attack.

A DOS attack is an attempt to make a server (or other resource) unavailable to its intended users. (1 mark)

1

ii The article also mentions that game players are being targeted by phishing.

Explain what is meant by phishing.

Phishing is the attempt to acquire sensitive information such as usernames, passwords, and credit card details by pretending to be a trustworthy source in an electronic communication. (1 mark) 1

e Game Mag also has an article on the problem of computer game piracy and the sale of illegal copied of games.

State the law that makes the copying of computer games illegal.

Copyright, Designs and Patents Act (1 mark)

1

f Game Mag has a web site. (see paper)

Identify two features used on this web page to aid navigation.

• Breadcrumb • Related posts • Main Menu • Site Search

1 mark for any bullet, max 2 marks 2

20 MegaFiles is secure file storage site. Users use a sign up page to create an account for the service. The design of the sign up page is shown below. (see paper)

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a i Using pseudocode or a language of your choice, show how a program could check that the password entered into Password1 has seven characters.

SET password TO password1 IF LEN(password) = 7 THEN SEND password valid TO DISPLAY ELSE SEND password invalid TO DISPLAY ENDIF

Use of LEN function (1 mark) Use of valid condition (1 mark) Use of IF END IF (1 mark) 3

ii Describe clearly, with reference to values and variables, the operation of the following pseudocode.

password_value is set to the contents of password1 password_confirm is set to contents of password2 (1 mark – for both inputs together)

IF statement checks if password_value and password_confirm contain the same data. (1 mark)

If they do then message “All good, let me in” is sent to the display (1 mark)

If it isn’t then the error is highlighted and displayed. (1 mark) 4

b When a user is logged into MegaFiles the service displays the percentage of the storage space the user’s files occupy. (see paper)

i The real number 14.72 is stored. Explain how a computer system will store a real number.

Number is stored in binary using a mantissa (1 mark) and an exponent (1 mark)

2

ii The rectangle bar is stored as a vector graphic. State one advantage of vector graphics when compared to bitmapped graphics.

• Resolution independent • Small file size • Elements/Objects of image can be

independently edited.

1 mark for any one bullet 1


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Detail of Sources / Mark Allocations and Balance

Question Unit Area Content Marks

1 SDD Low-‐level operations and computer architecture

Use of binary to store: integers 1


Basic computer architecture: processor(ALU) 1

3 ISDD Structures and links (database) good design to avoid data duplication and modification errors (insert. Delete. Update)

1

4 SDD User interface User requirements 1

5 ISDD Testing Links and navigation 1

6 SDD Computational Constructs expressions to return values using arithmetic operations (mod)

1


graphics (bit-‐mapped) 3

8a SDD Design notations other contemporary design notations 1

8b SDD Design notations other contemporary design notations 1

9 ISDD Structures and links (web-‐based)

relative and absolute addressing 2

10 ISDD Environmental impact Energy use 2

11 ISDD Structures and links (database) sort (on multiple fields) 2


Use of binary to store: characters 1

13 ISDD Media types Factors affecting file size and quality. 2

14a ISDD Technical implementation (hardware requirements)

device type (tablet/smartphone) 2

14b ISDD User interface User requirements 2

14ci ISDD Media types Standard file formats: graphics: jpeg, bmp, gif, png 1

14cii ISDD Media types Factors affecting file size and quality 2

14d ISDD Technical implementation peer-‐to-‐peer, client/server 2

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(network/connectivity)

14e ISDD Structures and links (web-‐based)

accessibility 1

15ai SDD Data types and structures 1-‐D arrays 1

15aii SDD Computational constructs use of selection constructs including simple and complex conditional statements and logical operators

1

15aiii SDD Design notations pseudocode to exemplify programming constructs 1

15aiv SDD Computational constructs pre-‐defined functions (with parameters) 1

15b SDD Testing and documenting solutions

logic errors 1

15ci SDD Computational constructs conditional loop 1

15cii SDD Computational constructs conditional loop 1

15ciii SDD Algorithm specification input validation 1

15d SDD Computational constructs expressions to concatenate strings using the & operator

1

15e ISDD Technical implementation (storage)

cloud 1

16a ISDD Structures and links (web-‐based)

URL 1

16b ISDD Structures and links (web-‐based)

hyperlinks (internal, external) 2

16c ISDD Media types video: mp4, avi 2

16d ISDD Coding scripting languages (including JavaScript) 1

16ei ISDD Legal implications Data Protection Act 1

16eii ISDD Legal implications Data Protection Act 1

16f ISDD Structures and links (database) database operations: sort (on multiple fields) 2

17a SDD Computational constructs expressions to assign values to variables 1

17b SDD Algorithm specification Exemplification and implementation of algorithms 5

17c SDD Low-‐level operations and Translation of high-‐level program code to binary 2


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computer architecture (machine code): interpreters

17d SDD Testing and documenting solutions

readability of code (internal commentary, meaningful identifiers, indentation)

2

18a SDD Low-‐level operations and computer architecture

interfaces 1

18b ISDD Technical implementation (network/connectivity)

wireless 1

18ci SDD Algorithm specification Exemplification and implementation of algorithms 3

18cii SDD Computational constructs pre-‐defined functions (with parameters) 2

18d ISDD Security precautions firewalls 2

18e ISDD Security precautions security protocols 1

19ai ISDD Structures and links (database) database structure: linked tables 2

19aii ISDD Structures and links (database) database structure: foreign keys 1

19b ISDD Structures and links (database) field types (object) 1

19c ISDD Structures and links (database) validation (range) 1

19di ISDD Security risks DOS (Denial of Service) Attack 1

19dii ISDD Security risks phishing 1

19e ISDD Legal implications Copyright, Designs and Patents Act 1

19f ISDD User interface User requirements: navigation 2

20ai SDD Design notations Exemplification and implementation of algorithms 3

20aii SDD Design notations Exemplification and implementation of algorithms 4

20bi SDD Low-‐level operations and computer architecture

real numbers 2

20bii SDD Low-‐level operations and computer architecture

graphics (bit-‐mapped and vector) 1

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Balance of Marks

ISDD/SDD

Area ISDD SDD Grand Total

Algorithm specification 9 9 Coding 1 1 Computational Constructs 9 9 Data types and structures 1 1 Design notations 10 10 Environmental impact 2 2 Legal implications 3 3 Low-‐level operations and computer architecture 12 12 Media types 7 7 Security precautions 3 3 Security risks 2 2 Structures and links (database) 10 10 Structures and links (web-‐based) 6 6 Technical implementation (hardware requirements) 2 2 Technical implementation (network/connectivity) 3 3 Technical implementation (storage) 1 1 Testing 1 1 Testing and documenting solutions 3 3 User interface 4 1 5 Grand Total 45 45 90

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